Trench digger



TRENCH DIGGER Filed Dec. l, 1958 2 Sheets-Sheet 1 ATTORNEYS Aug. l5, 1939. o. WERNER ETAL TRENCH D [GGER Filed Dec. l, 1938 2 Sheets-Sheet 2 .mlm

m, c/BSEPHHEL ENE/f,

[vf/A Apg L M ATTORNEYS Patented Aug. l5, 1939 f :mENcn moana Otto Werner, College Point, and Joseph Helenek, Flushing, N. Y., assignors of one-third to said Werner, one-third to said Helenek, and onethird to John J. Makofske, Hempstead, N. Y.

Application December 1, 1938, Serial No. 243,313

5 Claims.

This invention pertains to motor driven devices for digging trenches, and its object is to provide a simple, economical and effective device of this character capable of rapidly digging a substantially rectilinear trench of constant depth and cross-section, or a trench of a desired curvature or a combination of these two, such as is required for the laying of pipe, curbstones, etc.

'Ihe invention comprises in its essentials, a motor driven tractor-a standard form of caterpillar tractor may be used--to which is rigidly secured a projecting framework mounting at its projecting end a digging device, likewise rigidly secured to the framework, and consisting of a pointed digging shield having an upwardly inclined central ridge and oppositely sloping sides, with a pair of spaced moldboards for shaping the side walls of the trench extending rearwardly from theshield, the moldboards in turn being provided above the ground line with outwardly and rearwardly projecting vanes for sweeping the loose earth thrown up by the shield away from the edges of the trench, whereby the trench is cleanly cut and no loose earth permitted to fall back into it.

Although various motor driven devices have heretofore been proposed for digging furrows, trenches, etc., those of which we are aware either operate on a wholly different principle from the present invention and are highly complicated and expensive, such as those employing a series of excavating buckets mounted on a power driven belt; or else are inherently incapable by virtue of their constructions, of digging a cleanly cut trench of constant depth which follows precisely a desired rectilinear or curved line or combination thereof. Examples of the latter are the various types of tractor driven plows` and trench diggers in which the excavating member is loosely coupled to the tractor, for example, through a link-coupling, whereby the excavating member, plow, etc., may ride around and over hard objects, with the result that it is impossible with such device to obtain a substantially rectilinear trench of constant depth or one accurately following a desired course, such as is required in the laying of pipe, curbstones, etc. Moreover, the vast majority of devices of this character that have come to our attention are nothing more than plows in the ordinary sense of the word, capable of forming only roughly V-shaped furrows of loose earth and incapable of digging a smooth-walled, cleanly cut trench, for example, a relatively deep trench of rectangular contour, such as can be quickly dug with the present invention.

In the drawings:

Fig. 1 is a view in side elevation and Fig. 2 is a plan view of one form of trench digging device in accordance with our invention; while Figs. 3 and 4 are similar views respectively, of a modified form which differs from the above in that the framework supporting the digging device is elevatable and the digging device itself is, rotatable about a horizontal axis by mechanisms controlled from the tractor.

Referring to Figs. 1 and 2, the mechanism comprises a motor driven tractor I of the caterpillar type of standard construction and hence requiring no detailed description, to the opposite sides of which a pair of I-beams, channel members, or the like, 3, 4 are rigidly attached, as for example by mounting on the axles 5, 6 of the tractor. Members 3, 4 project beyond the tractor and are bent toward one another in the projecting por--v tions at 1, 1 and thence parallel at 8, 8. The digging device or trencher 9 is rigidly mounted between the extensions 8, 8.

Device 9 includes an excavating shield I0 of steel plate or the like, comprising oppositely sloping, concave wings I I, I2 tapering to a sharp projecting nose I3 and intersecting along a central ridge I4 curving upwardly from the nose and thence reversing its curvature toward the top as shown, with the base portions I5 of the wings lying in a common, substantially horizontal plane. Integral with this shield are a pair of spaced moldboards or panels I6, I1 of steel plate or the like, which extend rearwardly from opposite sides of the shield with their lower edges in the same plane as the base I5 of the shield, and braced apart by a transverse member I8. In the construction shown these moldboards are arranged in vertical planes for imparting a rectangular contour to the trench, but it will be understood that they may be so inclined or shaped as to impart any desired sectional contour to the trench. Bolted, Welded or otherwise secured to the moldboards I6, I1, are vertically extending bars I9, 20, here shown as small I bars, each of which is provided with a series of bolt holes, such as 2|, by means of which the trencher 9 may be adjustably bolted at a desired elevation by means of bolts 22 and nuts to the frame extensions 8, 8. Bolted or otherwise secured to the moldboards I6, I1 are a pair of outwardly and rearwardly extending vanes 23, 24, which terminate at their lower edges of the ground line 25 of a trench 26 being dug and for the purpose of sweeping the loose earth thrown up by the shield away from the surface edges of the trench as described below.

In operation the tractor is driven in the direction indicated by the arrow 21 whereby the solid earth 28 is loosened andv turned up above the ground line 25 by the shield, as shown at 29, and thrown of! to the right and left, as indicated at III, along the sides of the trench 29 being dug. Thereafter the vanes 23, 24, moving along above the ground line behind the shield, sweep the loose earth well away from the edges of the trench so that none falls back. Meantime the moldboards I9, I1 moving along in the trench behind the shield impart a smooth surface to the sidewalls of the trench while the base I5 of the shield similarly imparts a smooth surface to the bottom of the trench. The depth of cut may of course be adjusted as desired by attaching the trencher to the frame extensions 8, 8 through appropriate bolt holes 2 I.

In the drawing the tractor is arranged to be driven backwards and to pull the digging device through the ground, an arrangement which has been found in practice to give eminently satisfactory results. The position of the tractor may of course be reversed so that the drive is forward and the digging device pulled along behind it. Also the digging device may be arranged to be pushed along ahead of the tractor.

Due to the rigid mounting of the framework 3, 4 on the tractor and the rigid mounting of the trencher 9 on this framework, the trencher must follow precisely the direction of the tractor, so that if the tractor is driven in a straight line the trench will necessarily be straight and in general will accurately conform to the course followed by the tractor. Likewise due to the rigid mountings referred to and the weight of the tractor, the trencher will be forced to excavate to a constant depth. It has been found in practice that the trencher will follow accurately the direction of the tractor and will excavate to a constant depth irrespective of variations in density oi the earth or of obstacles, except such obstacles of course as are so large and massive that the tractor cannot pull the trencher through them,'in which event the tractor must be stopped and obstacles of this character, such as large boulders, etc., removed with pick and shovel, etc. The device requires but one man for operation and excavates with such rapidity that it can replace a large number of men working with pick and shovel or with a power driven shovel, such as a steam shovel.

Figs. 3 and 4 show a slightly modified eonstruc tion wherein the trencher 9 is mounted upon an extension 3I of a frame 32 which carries a surface grading element 33 of the familiar type of surface grading tractor 34. In this case, the frame 32 is mounted upon and rotatable about the rear axle 6 of the tractor whereby the trencher 9 may be raised or lowered as desired. For accomplishing this, a piston 35, pivotably linked to frame 32 as shown, operates in a cylinder 36 connected by tubing 3l to a. motor actuated pressure tank 38 for actuating the piston 35 by means of hydraulic or pneumatic pressure, the apparatus being so 'arranged in a known manner that the piston can'be rigidly maintained in any desired position-thereby to hold the trencher 9 to any desired depth of cut.

Asa further refinement the trencher 9 is in this instance rotatably mounted on a horizontal axle 39 mounted between vertical members 40 carried by the frame extension 3 I. For adjustably controlling from the tractor the angular setting of the trencher, a second piston 4I is provided which is pivotably linked to the trencher at 42, the piston in turn operating within a cylinder 43, pivotably linked to the frame at 44, and connected by means of tubing 45 to the pressure tank 38. In this way the trencher may be rotated to any desired position and held there as the digging proceeds. 'This is desirable in digging through earth containing numerous hard objects, such as rocks, etc., because when the nose of the shield strikes such an object it tends to dig in more deeply or to ride over the object, which tendency may be oilset by appropriately tilting the shield slightly.

What we claim is:

1. A trench digger comprising: a motor driven tractor supported on its opposite sides on movable conveying means for preventing longitudinal and lateral tilting of said tractor with respect to the ground, a projecting framework rigidly mounted thereon, a trench digging device rigidly secured to said framework and disposed laterally between said conveying means, said device including an excavating shield having an inclined central ridge and oppositely sloping sides, spaced moldboards extending rearwardly of said shield, and earth displacing varies extending from the rear of said shield above the ground line.

2. A trench digger comprising: a motor driven tractor supported on its opposite sides on movable conveying means for preventing longitudinal and lateral tilting of said tractor with respect to the ground, a projecting framework rigidly mounted thereon, a trench digging device rigidly secured to said framework and disposed laterally between said conveying means, said device including an excavating shield having an inclined central ridge and oppositely sloping sides, spaced moldboards extending rearwardly of said shield, earth displacing vanes extending from the rear of said shield above the ground line, and means for' adjusting the elevation of said excavating device with respect to said framework for altering the depth of cut.

3. A trench digger comprising a motor driven tractor supported on its opposite sides on movable conveying means for preventing longitudinal and lateral tilting of said tractor with respect to the ground, a projecting framework mounted thereon, a trench digging device rigidly secured to said framework and disposed laterally between said conveying means, said device including an excavating shield having an inclined central ridge and oppositely sloping sides, spaced moldboards extending rearwardly of said shield, earth displacing vanes extending from the rear of said shield above the ground line, and means controllable from' said tractor for elevating said framework and for rotating said shield about a horizontal axis and also for rigidly locking said framework and shield in desired positions.

4. A trench digger comprising: a motor driven tractor supported on its opposite sides on movable conveying means for preventing longitudinal and lateral tilting of said tractor with respect to the ground, a projecting framework carried thereby, means rigidly securing said framework against vertical and lateral displacements with respect to said tractor, a trench digging device rigidly mounted on said framework and disposed laterally between said conveying means, said device including a pointed excavating shield having a central inclined ridge and oppositely sloping sides, spaced moldboards extending rearwardly from the opposite sides of said shield and extending vertically from the base of said shield to a height exceeding the trench depth, and a pair of vanes l extending outwardly and rearwardly from said moldboards for sweeping earth away from the surface edges of said trench. y

5. A` trench digger comprising: a motor driven tractor supported lon its opposite sides on movable conveying means for preventing longitudinal and lateral tilting of said tractor with respect to the ground, a projecting framework carried thereby, means controlled from said tractor for rigidly securing said framework against vertical and -lateral displacements with respect to said tractor, a trenchdigging device rigidly mounted on said framework and disposed laterally between said conveying means, said device including a. pointed excavating shield having a central inclined ridge and oppositeiy sloping sides, spaced moldboards extending rearwardly from the opposite sides of said shield and extending vertically'from the base of said shield to a height exceeding the trench depth, a pair of vanes extending outwardly and rearwardly from said moldboards for sweeping earth away from the surface edges of said trench,

.saidmeans controlled from said tractor being reieasable for rotating said framework and independently thereof said digging device about horizontal axes.

OT'IO WERNER. JOSEPH HELENEK. 

